POWRE: Kinetic Analysis of the AMPA Receptor After C-Terminal Modification

POWRE：C 端修饰后 AMPA 受体的动力学分析

• 批准号: 9806215
• 负责人: Amy Arai
• 金额: $ 6.68万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9806215&HistoricalAwards=false
• 关键词: POWRE; Kinetic; Analysis; AMPA; Receptor

IBN 98-06215 ARAI Neurons throughout the brain contain a calcium-activated protease called 'calpain' that can cleave various intracellular proteins. It has been shown that the moderate increase in intracellular calcium produced by a few bursts of synaptic activity is sufficient to activate this enzyme. Such activity under the proper circumstances induces a long lasting enhancement of synaptic transmission called 'long-term potentiation' (LTP), which is thought to be one of the mechanisms responsible for encoding memory. Suppression of calpain in fact prevents both LTP and memory formation, which suggests that this enzyme plays an essential role in these processes. Expression of LTP is now commonly thought to involve a change in currents through AMPA receptors, a subtype within the glutamate receptor family, that mediates excitatory synaptic transmission between most neurons in higher brain regions. It is thus of particular interest that AMPA receptors were recently found to be cleaved by calpain near their intracellular C-terminal, and that the domain removed by proteolysis contains target sites for kinases and a site which anchors the receptor to cytoskeletal proteins. The goal of this project is to identify whether and in what way C-terminal modification of the AMPA receptor by calpain alters the functional properties of this receptor. It will be specifically tested (1) whether direct application of activated calpain into neurons changes the time course of the current flow through the receptors, (2) whether AMPA receptors truncated at their C-terminal exhibit characteristic alterations in their physiological properties, and (3) whether modulation of AMPA receptors by kinases is altered after truncation. The proposed experiments supported by this POWRE award represent a new direction for Dr. Arai and will give her the opportunity to learn new skills in the field of molecular biology which will complement her expertise in neurophysiology. Acquiring thes e skills will be critical for her career goal to start an independent research laboratory, to expand her research scope, and to develop further her leadership in the field of AMPA receptor research and synaptic plasticity.

IBN 98-06215 ARAI 整个大脑的神经元含有一种钙激活的蛋白酶，称为“钙蛋白酶”，可以切割各种细胞内蛋白质。 已经表明，由突触活动的几次爆发产生的细胞内钙的适度增加足以激活这种酶。在适当的情况下，这种活动会诱导突触传递的长期增强，称为“长时程增强”（LTP），这被认为是负责编码记忆的机制之一。 抑制钙蛋白酶实际上阻止了LTP和记忆的形成，这表明这种酶在这些过程中起着重要作用。 现在普遍认为LTP的表达涉及通过AMPA受体的电流的变化，AMPA受体是谷氨酸受体家族中的一种亚型，介导高级脑区域中大多数神经元之间的兴奋性突触传递。 因此，特别令人感兴趣的是，最近发现AMPA受体在其细胞内C-末端附近被钙蛋白酶切割，并且通过蛋白水解去除的结构域包含激酶的靶位点和将受体锚定到细胞骨架蛋白的位点。 该项目的目标是确定钙蛋白酶对AMPA受体的C末端修饰是否以及以何种方式改变该受体的功能特性。将具体测试（1）将活化的钙蛋白酶直接应用于神经元是否改变通过受体的电流的时间过程，（2）在其C-末端截短的AMPA受体是否表现出其生理特性的特征性改变，以及（3）在截短后激酶对AMPA受体的调节是否改变。 这项POWRE奖支持的拟议实验代表了Arai博士的新方向，并将使她有机会学习分子生物学领域的新技能，这将补充她在神经生理学方面的专业知识。 获得这些技能将是她的职业目标，开始一个独立的研究实验室，扩大她的研究范围，并进一步发展她在AMPA受体研究和突触可塑性领域的领导地位的关键。